Artificial photosynthesis for CO2-to-ethylene conversion enabled by dye-sensitised carbon nitrides

点击翻译按钮获取中文摘要

Photoelectrochemical (PEC) cells are unique devices combining direct solar light conversion into chemical bonds with the compactness and catalytic tuneability of electrolysis. Photoelectrocatalysis is a promising solution for the scalable synthesis of solar fuels, i.e. chemicals with deliverable energetic content, and photoreforming, that is the light-driven conversion of waste into added-value products. On the cathodic side, solar-driven CO2 reduction to hydrocarbons and other organic molecules is a promising venue to solar fuels synthesis and strategy for decarbonisation. For the anodic reaction, glycerol has been proposed as excellent photoreforming substrate for its facile oxidation and its current overproduction as a byproduct of the synthesis of biodiesel. However, glycerol oxidation usually leads to a mixture of products, including glyceraldehyde and 1,3-dihydroxyacetone, with the latter being more valuable. The purpose of this Ph.D. project will be to design and fabricate a stand-alone PEC device comprising a photocathode for high-rate synthesis of C2-C3 hydrocarbons from CO2 and a photoanode for the selective photoreforming of glycerol to 1,3-dihydroxyacetone in acidic environment. The incorporation of a tandem perovskite solar cell in a copper-based photocathode will enable conversion of CO2 to hydrocarbons at very positive onset potentials and record-breaking photocurrents. On the other hand, different light-absorbing semiconductors, including polymeric carbon nitrides and perovskites, will be screened for the fabrication of a photoanode for glycerol oxidation. Selectivity of the anodic reaction will be achieved either by state-of-the-art Pt-Bi electrocatalysts or substrate-specific enzymes. Finally, the two electrodes will be combined in a stand-alone device for a bias-free, solar-driven complete redox cycle.